40 INFERIOR OOLITE AMMONITES. 



when the body- chamber is present (PL XIII, fig. 2), cannot be said to be quite the 

 rule in the Liocerata, though some old specimens of other species exhibit a tendency 

 this way. It is most certainly a feature in Oppelia, and is worthy of notice in 

 that connection. 1 



When treating of the genus Lioceras I have stated my reasons for choosing 

 this species as the type of the genus in preference to any of the other species 

 which Hyatt placed in it, and etymologically this name applies to the species very 

 well. 2 The specific name was probably given by Reinecke on account of the 

 opalescent tints sometimes seen on the inner coat of the test. 



I have collected Lioc. opalinum at Haresfield Hill, 3 in bed No. 15 (p. 43), 

 plentifully, well-preserved, and of large size, with the mouth-border complete 

 (PL XIII, fig. 3). In bed No. 16 I have found it of smaller size and not so 

 frequently. I have obtained it from the same horizons at Frocester Hill ; and the 

 same remarks as to size and position apply to beds Nos. 4 and 5 of the Coaley 

 Wood Section. From North Nibley I have some small specimens from bed No. 6, 

 and the late Mr. E. Witchell, F.G.S., showed me some specimens which he had 

 obtained at Little Sodbury, near Yate. I do not know of its occurrence in 

 Somerset, though it is probable that its real bed occurs at the bottom of some of 

 the quarries at Haselbury, Misterton, &c, but has been overlooked. In Dorset 

 Burton-Bradstock Cliff is the chief locality, whence I have many specimens, but 

 none over three inches in diameter. From Stoke Knap I have it ; but it is very 

 scarce. I have not seen it from the Sherborne and Bradford- Abbas side of the 

 County, and it is probable that the whole zone is entirely absent. Through the 

 kindness of Mr. E. A. Walford, F.G.S., I have seen some specimens from Otley 

 Hill, near Hook Norton, North Oxfordshire (p. 52) ; and by the kindness of Mr. B. 

 Thompson, F.G.S., a specimen from New Duston, Northamptonshire (p. 48), 

 with specimens of Lioceras comptum (Reinecke). 



Plate XIII, figs. 1, 2, show a large typical specimen of this species, the test 

 of which is extremely well preserved. In fig. 2 the rounded ventral area of the 

 body-chamber is noticeable ; and, as the ventral area is well-preserved and has 

 the test present, there can be no mistake about it. In Fig. 3 we have a portion 

 of a large specimen, five and a half inches in diameter, with the mouth-border, 

 while what this is in youth is partly indicated in fig. 12. These specimens came from 

 Haresfield Hill, Gloucestershire, from the bed No. 15 in the section at p. 43. 

 Figs. 4, 5, illustrate a smaller typical specimen, of a size to compare with Reinecke's 



1 I do not, however, consider that Oppelia is descended from Lioc. opalinum, because I think that 

 in Am. discoides, Zieten, we have one of the earliest forms of Oppelia-like species. Am. discoides occurs 

 just below Lioc. opalinum. 



2 Mios, smooth ; Kepas, horn. 



3 Marked as Standish Beacon on the Ordnance Survey Map. 



